Search

The oxygen environments of Fe+3-δ ions determine the magnetic anisotropy of M-type ferrites. The high annealing temperature increases the oxygen content and decreases the lattice strain in M-type SrFe9.4Cu0.8Sn0.5O19-d ferrites. The anisotropic field and the coercive field decrease with the increasing annealing temperature. Annealed at 1400 °C, a ferromagnetic resonance is observed at the frequency above 9.5 GHz, with the real part having a peak and the imaginary part of the permeability having a high plateau over a wide frequency range. It enables the microwave energy' dissipation by the magnetic loss. Furthermore, the extra oxygen ions ease up the dipole polarizations' rotation and significantly increase the dielectric permittivity. At thin thickness of 1.3 mm, the effective absorption bandwidth (R L ≤ − 10 dB) of SrFe9.4Cu0.8Sn0.5O19-d annealed at 1400 °C is 7.1+ GHz from 10.9 to 18+ GHz. SrFe9.4Cu0.6Sn0.6O19-d annealed at 1400 °C has the microwave absorption bandwidth of 8.8 GHz from 9.2 to 18+ GHz at 1.6 mm. Both are very promising microwave absorbing materials. [ABSTRACT FROM AUTHOR]

The non-photosynthetic vegetation – soil separation index (NSSI) and normalized difference vegetation index (NDVI) can be used to simultaneously estimate the fractional cover of non-photosynthetic vegetation (fNPV), photosynthetic vegetation (fPV), and bare soil (fBS) in vegetation ecosystems. However, these estimates suffer from problems due to shading by dense vegetation or topography. Based on field-measured data and on hyperspectral data acquired by unmanned aerial vehicles, we analyse how shading affects the morphology of NDVI-NSSI and enhanced vegetation index – NSSI (EVI-NSSI). We also investigate the simultaneous estimation of fNPV, fPV, and fBS. The results show that the NDVI-NSSI normalized difference feature space mitigates the impact of shade. Shade causes the NDVI-NSSI and EVI-NSSI to shift rightward parallel to the BS axis and leftward parallel to the PV axis, respectively. Although such shifts may hinder the determination of NPV, PV, and BS endmembers, they do not affect the spectral separation of NPV. Overall, with the NDVI-NSSI and EVI-NSSI methods, the estimation error for fNPV under shaded conditions is approximately 5% greater than that under illuminated conditions. Shaded green vegetation more strongly affects the estimation error of fPV and fBS in EVI-NSSI than in NDVI-NSSI, whereas fBS and fPV depend more strongly on shade than fNPV. [ABSTRACT FROM AUTHOR]

Traditional Chinese villages act as the essential carriers of China's rural heritage. Such villages are considered to retain living practices of intangible heritage through know-how, artistic and folk customs, as well as a well-preserved architectural appearance. However, their conservation is at stake due to degradation, abandonment, and urbanization. Spatial cognition is one way of bringing people to the matter of what is important to conserve (attributes) and why they are important (values). This is done by analysing how people perceive and value rural heritage. Traditional methods of gathering spatial cognition data, such as laborious fieldwork or subjective qualitative analyses, often fall short of providing a holistic representation of real-world experiences. This article presents an innovative method for analysing cognitive features in traditional village spaces using an immersive virtual reality equipped with an eye-tracking system. We selected Cheng and Jitou, two traditional Chinese villages, as our case studies. In two virtual reality environments, we captured accurate 3D cognitive data, including participants' locomotion, gaze point, and sightline. The results indicate that the accessibility of village roads affects the distribution of people's locomotion, which in turn affects the distribution of people's areas of interest; the changes in the rhythm of the sightline scale reflect the rhythm of spatial changes in the villages. By broadening the understanding of spatial cognition in traditional Chinese villages related to people's values, this paper sheds light on an alternative approach to assess the cultural significance of such villages for higher conservation and sustainability. [ABSTRACT FROM AUTHOR]